Manchester City are not ready to put a date on Sergio Aguero's return to action, yet Pep Guardiola expects the club's record goalscorer to "help us in the decisive moments" this season.
Aguero underwent meniscus surgery last June and then saw a hamstring injury hamper his initial comeback in October.
These issues have limited the 32-year-old to just nine appearances in all competitions this season, which have yielded two goals.
Aguero also had to self-isolate earlier in January when he was set for an outing in the FA Cup and last week revealed he had tested positive for coronavirus.
Into the final six months of his City contract, Guardiola is keen to have Aguero back available, although he detailed how the striker was laid low by the effects of COVID-19.
"The important thing is when we text him during the first three, four days, he struggled, he felt so tired, but today he sent a message to the backroom staff to say he feels much better," Guardiola said ahead of Tuesday's trip to West Brom.
"Now he needs to test negative and abide by the protocols, and then start to come back here and move and see how he feels, day by day.
"I cannot tell you [when he will be back], I don't know how he will react in the first days when we start to train."
There have been only three starts for Aguero this term, with his pitch time a meagre 260 minutes overall.
The Argentina international has scored with both of his shots in the Champions League but failed to register in the Premier League, having four efforts across five outings and passing up a big chance with his only shot on target against Newcastle United.
A contract extension remains on the agenda, though, and Guardiola sees Aguero rediscovering the scoring touch that has so far brought 256 goals in 316 games for City, netting with 19 per cent of his attempts.
"I don't know when he is coming back, February or March, but I'm so optimistic that he will give us until the end of the season some good, good months," Guardiola said. "I'm so optimistic.
"He is going to help us in the decisive moments, to give us the goals and the difference that we need. I'm so confident it's going to happen."
In 2018-19, as Vincent Kompany entered the final months of his contract, the former City captain put long-term injury troubles behind him to play a key role in their most recent title success.
Guardiola was asked if the plan was for Aguero to have a similar impact and replied: "Hopefully. Hopefully it's going to happen.
"But at the same time, Vincent had an incredible quality; after being two months injured in the gym, he can go out and play one training session and play incredibly well.
"Sergio doesn't know if he has this quality to immediately go out and do it. He needs the special sharpness and the first steps for this quality to score a goal, but it depends on him.
"At the end, we'll see him in the training session and on the pitch and it's easy to realise if he's fit or not.
"But hopefully he can help us with the special quality he has. That's why he is one of the best strikers ever - not just in England, all the time in football history."